Heretofore, a raw ore product such as coal has been cleaned by way of a method which includes rinsing and screening, removing surface water in a centrifuge or the like while the ore product is at ambient temperature, and then drying the ore product with a thermal dryer. A thermal dryer operates with air heated to 500.degree.-1200.degree. F. with an air flow per ton of coal being about 300,000-700,000 cubic feet. This high temperature high flow rate fluidizes dust and renders it bone dry whereby the high flow rate creates a pollution problem so that the outlet of the dryer requires a dust collector and a smokestack. The higher temperatures of the air in the thermal dryer are a potential hazard in view of the fact that many explosions are based on ignition of coal dust.
The method of the present invention overcomes the above disadvantages of the prior art as well as other disadvantages such as high initial cost, greater efficiency and/or uniformity of moisture content, lower operating costs, etc.